Mirrors have been in existence for years and have been used in interior building applications such as, for example, in bathrooms, as decorations, for furniture, etc., and for exterior applications. Mirrors generally are either first surface mirrors where the mirror coating is provided between the viewer and the supporting glass substrate, or second surface mirrors, where the supporting glass substrate is interposed between the viewer and the mirror coating. See, for example; U.S. Pat. Nos. 7,276,289 and 7,678,459; U.S. Publication Nos. 2006/0077580; 2007/0178316; 2008/0073203; 2008/0164173; 2010/0229853; 2011/0176212; and 2011/0176236. The entire contents of each of these patent documents are hereby incorporated herein by reference.
FIG. 1 is a cross sectional view of a conventional second surface mirror. The mirror in FIG. 1 includes a mirror coating on glass substrate 100, the mirror coating being composed of silicon nitride layer 101, sputter-deposited aluminum reflective layer 102, silicon nitride layer 103, and optional PPF (permanent protective film) or paint layer 108. Despite the fact that aluminum is highly reactive, it possesses defense against corrosion and tarnishing, namely by way of forming a very thin stable aluminum oxide layer at a surface thereof which prevents/reduces the rest of the aluminum in the aluminum reflective layer from further oxidation. Aluminum is also cheaper than silver. However, the mirror of FIG. 1 suffers from the following problems. First, its visible reflectance is not as good as a high priced silver mirror. Aluminum mirrors are cheaper than silver mirrors, but provide for a lower amount of visible light reflectance, This problem affects the general quality of reflected images and often limits the use of such mirrors to clean-cut applications using thinner glass such as glass less than 4 mm thick. Thicker glass, used for example in beveled mirrors, absorbs a greater portion of light and often requires the use of reflective material which reflectance higher than that of aluminum. Second, its glass side reflective color tends to shift toward the blue color range (compared to a silver mirror), i.e., a blue color shift, which some consider to be aesthetically undesirable. In home/residential mirrors, especially under fluorescent light, the blue shift of the spectrum adds “cool cast” to the reflected image which some believe to be aesthetically undesirable. Given that fluorescent lights are becoming more popular in home/residential and certain commercial/office applications, there is a need in the art to add a “warm cast” to aluminum mirrors in order to make reflected images appear more natural.
Thus, it will be appreciated that there is a need in the art for improved mirrors and/or methods of making the same, where one or both of the problems identified above are addressed. Thus, certain embodiments of this invention relate to mirrors that solve one or both of the problems discussed above.
Certain example embodiments of this invention relate to mirrors including at least one of: (a) a first reflective layer of or including aluminum and a second reflective layer of or including silver or the like, and/or (b) a color tuning layer between first and second reflective layers. The mirrors may be second surface mirrors in certain example embodiments of this invention.
Certain example embodiments of this invention relate to providing a thin reflective layer of low refractive index material (e.g., silver or copper) that is sputter deposited on the glass substrate (directly or indirectly) so as to be located between the glass substrate and an aluminum inclusive reflective layer. This provides adds a “warm cast” to reflected images. In other words, compared to reflected images from the conventional mirror discussed above, this shifts the reflection spectrum to longer wavelengths as well in order to increase the intensity of reflected visible light. This allows the images from the mirror to appear more pleasant, and permits better image quality compared to the use of only an aluminum reflective layer as in the conventional mirror discussed above.
Certain example embodiments of this invention relate to mirrors including a color tuning layer, typically of a transparent dielectric material, provided between first and second reflective layers. The reflective layers may be of or include aluminum and/or silver. The color tuning layer embodiment may or may not be used in combination with the embodiment where both aluminum and silver reflective layers are provided.
In certain example embodiments of this invention, there is provided a mirror, comprising: a glass substrate; a reflective film on the glass substrate, the reflective film comprising or consisting essentially of a first metallic or substantially Metallic layer and a second metallic or substantially metallic layer; and wherein the first metallic or substantially metallic layer of the reflective film comprises silver (or copper), and the second metallic or substantially metallic layer of the reflective film comprises aluminum, and wherein the first metallic or substantially metallic layer comprising silver (or copper) is located between at least the glass substrate and the second metallic or substantially metallic layer comprising aluminum.
In certain example embodiments of this invention, there is provided a mirror comprising: a glass substrate; a reflective film on the glass substrate, the reflective film comprising a first metallic or substantially metallic layer and a second metallic or substantially metallic layer; and wherein the first metallic or substantially metallic layer of the reflective film comprises material selected from the group consisting of silver, copper and aluminum; wherein the second metallic or substantially metallic layer of the reflective film comprises aluminum, and wherein the first metallic or substantially metallic layer comprising silver is located between at least the glass substrate and the second metallic or substantially metallic layer comprising aluminum; and a dielectric film provided between and directly contacting the first and second layers of the reflective film.